No'Y' bb question - Dual antennas???

[Ayrow]

I know this is a dumb question, but I am going to ask anyway....

Trying to increase the reception of the new digital system Indianapolis is on - lots of garble and fringe reception.
I have two of the Radio Shack window mounted (through the window) whip antennas mounted on my truck.
Will using both of them through a generic BNC 'Y' splitter help at all? Will it hurt??
Is there something I can do that will work better? Obviously I know nothing about antennas, but I figured since I had two of them on there, I might as well utilize them.

Help!

Thanks.

 

[n5ims]

Most often it will hurt. When working with a single frequency (or very limited range of frequencies), you can phase two antennas to create a directional signal, but this is not very affective in a moving car.

You may want to check your reception with the attenuator both on and off on your scanner. While it may sound like you don't have enough signal for good reception, you may actually be getting too much (as strange as that sounds). Most scanners have receivers that overload quite easily, causing it to sound very similar to fringe signal reception.

 

[ridgescan]

+1 on n5ims hey but you know what would be a kick in the ass-run an antenna switch so you can run off one or the other!! If they are on either side of the vehicle like I suspect, your reception on either given one will not recieve signals as strong coming in from the opposite side of the vehicle....that's where the antenna on the other side would come in I dunno-sounds like a fun experiment to me anyways 73s

 

[KC0QNB]

I built a set of phased antennas back in my cb days, it (they)actually worked on RX quite well it may be a simple matter to use a pin diode type control system, I have seen them for 4 antennas not two but then it would be twice as easy, (well seemed like a good thing to say) anyway google for a two antenna (element) pin diode phased array and see what pops up post results here KK?

 

[zz0468]

I built a set of phased antennas back in my cb days, it (they)actually worked on RX quite well it may be a simple matter to use a pin diode type control system, I have seen them for 4 antennas not two but then it would be twice as easy, (well seemed like a good thing to say) anyway google for a two antenna (element) pin diode phased array and see what pops up post results here KK?

The 4 antenna pin-diode controlled arrays are direction finding antennas, not gain antennas. Switching them isn't going to buy you anything.

To the op: The best single thing you could do to improve reception is to lose the glass mount antennas. Go with a mag mount if you absolutely refuse to drill a hole in your car, or better still, drill a hole in the roof, and install a proper gain antenna. You'll probably gain 6 or more db over the glass mount.

 

[daedalus]

ZZ0468 is right on. Glass mount antennas are generally less effective than a wet piece of string unless you are receiving a very strong signal. Either drill the hole or get a trunk mount antenna.

 

[ridgescan]

ZZ0468 is right on. Glass mount antennas are generally less effective than a wet piece of string unless you are receiving a very strong signal. Either drill the hole or get a trunk mount antenna.

I respectfully differ-I am running a glass mount 800MHZ centerloaded whip rated at 3db gain. I get VERY GOOD reception at 800MHZ, good reception at UHF,/VHF high, and OK reception at VHF low! Amazing for what it is. So my point is they are not to be ruled out as "a wet noodle" alltogether. 73s

 

[jon_k]

I respectfully differ-I am running a glass mount 800MHZ centerloaded whip rated at 3db gain. I get VERY GOOD reception at 800MHZ, good reception at UHF,/VHF high, and OK reception at VHF low! Amazing for what it is. So my point is they are not to be ruled out as "a wet noodle" alltogether. 73s

The higher the frequency the better it will travel through a dielectric like glass. I think that's why 800mhz antennas were made like this in such large number.

I wouldn't rate anything like a wet noodle. Even a twist tie stuck in the ANT jack (I've tried this!) will pull signals in with mediocre performance. So if you've got anything better then that -- you've got pretty good performance. Unless of course you've stuck noodles into your BNC connectors. (I've tried this too! For some reason no matter what wavelength I cut the noodles for... I get horrible attenuation. Was thinking of starting a new thread, but first any suggestions?)

Is there something I can do that will work better? Obviously I know nothing about antennas, but I figured since I had two of them on there, I might as well utilize them.

It wont hurt, but it won't help. It'll cause interference rather than pull distant stations in.

Build this mental image. Imagine you put the Y splitter in. Put one antenna on the east side of a room. Put one antenna on the west side of the room. Tune into a transmitter far away coming from the west side of the town. Your western antenna will pick up the radiowave slightly faster than the eastern antenna. It will essentially create a ghost of the signal received moments before, this will effectively cause interference since the receiver has already received that signal -- and to receive it again will step on the other radio waves from the western antenna. So receiving a wave slightly out of phase of the first set of received waves will not amplify the distant station. It'll cover it up if anything.

Do anything but this to pull a distant station. Switch antenna designs or wavelengths, increase antenna mount height. Anything you implement should be better than two antennas spaced apart. It was a good idea, but once you see what this effectively does, you can tell why it won't work.

 

[zz0468]

I respectfully differ-I am running a glass mount 800MHZ centerloaded whip rated at 3db gain. I get VERY GOOD reception at 800MHZ, good reception at UHF,/VHF high, and OK reception at VHF low! Amazing for what it is. So my point is they are not to be ruled out as "a wet noodle" alltogether. 73s

A wet noodle makes a fine antenna, if you're not overly concerned about performance. I've used glass mount antennas, in fact, I installed one on my wife's car for her ham rig. It works ok, and she doesn't complain about poor reception. But in this case, the OP is specifically seeking improvements.

I've done side by side experiments with glass mount, and roof mount antennas. In my measurements, a quarter wave spike at both 440 and 800 MHz outperformed a so-called 3 db gain glass mount by several db. The disparity between a glass mount and quarter wave at VHF is even higher.

So... If you absolutely CAN'T drill a hole or use a mag mount, then use a glass mount. If it's not good enough, drill a hole.

 

[af5rn]

I respectfully differ-I am running a glass mount 800MHZ centerloaded whip rated at 3db gain. I get VERY GOOD reception at 800MHZ, good reception at UHF,/VHF high, and OK reception at VHF low! Amazing for what it is. So my point is they are not to be ruled out as "a wet noodle" alltogether. 73s

But you're comparing apples to oranges. You're comparing a single band antenna performance, on the band it is cut for, against an all-band whip performing on a 1000mhz spread. Glass mount or not, a single band antenna cut for the single band you are monitoring is always going to be your best bet. But on a broadband scanner, your analogy doesn't stand up.